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Chemistry Past Questions

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1,623 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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1,623 questions

Question 1 of 20 1,623 total questions

Question 751

waec 1991

Esterification of propane 1,2,3-triol and unsaturated higher carboxylic acids will produce

Afats

Bsoap

Cmethly-propanoate

Dalkanols

Eoils

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Question 752

waec 1991

2NaNO3 → 2NaNO2 + O2. From the equation above, what is the volume of oxygen produced at s.t.p. when 8.5g of 2NaNO3 is heated until no further gas is evolved? (2NaNO3 = 85, molar volume of gases at s.t.p. = 22.4dm3)

A1.12dm³

B2.24dm³

C4.48dm³

D11.2dm³

E22.4dm³

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Question 753

waec 1991

Consider the reaction represented by the equation below: H2(g) + 12(s) ⇌ 2HI(g) ∆H negative. Which of the following takes place when the temperature of the reaction vessel is decreased?

Athe gases condense

Bthe yield of hydrogen increases

Cthe concentration of the reactants remain constant

Dmore of the hydrogen iodide decomposes

Ethe yield of hydrogen iodide increases

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Question 754

waec 1991

CH₄_(g) + 2O₂_{(g) → 2H₂O_(l) + CO₂_(g) ∆H = 890KJ mo-₁ ∆H in the reaction represented by the equation above is the enthalpy of}

Aformation

Bcombustion

Csolution

Dactivation

Eneutralization

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Question 755

waec 1991

A compound which liberates carbon (IV) oxide from a hydrogentrioxocarbonate (lV) could have the molecular formula

AC₂H₅OH

BC ₃H ₄

CHCOOH

DH₂O₂

EC₆H₆

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Question 756

waec 1991

In which of the following are the substances arranged in their correct order of increasing melting point?

ASodium chloride, sulphur, diamond

BDiamond, sodium chloride, sulphur

CSulphur, sodium chloride, diamond

DDiamond, sulphur, sodium chloride

ESulphur, diamond, sodium chloride

View Explanation & Discuss

Question 757

waec 1991

Which of the following statements is not correct? Group 7 elements

Aare diatomic

Bare good oxidizing agents

Care highly electronegative

Dhave relatively low ionization potentials

Ehave high electron affinity

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Question 758

waec 1991

Which of the following modes of motion is exhibited by the particles of a solid?

AVibrational and random motion

BVibrational and translational motion

CTranslational and random motion

DVibrational motion only

ETranslational motion only

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Question 759

waec 1991

The products of the electrolysis of dilute sodium chlorid solution with platinum electrodes are

Ahydrogen and oxygen

Boxygen and chlorine

Cchlorine and water

Dsodium amalgam and chlorine

Esodium hydroxide and water

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Question 760

waec 1991

Which of the following formula is that of a dicarboxylic acid?

A(CH₃CH ₂)₂CHCOOH

BCH₂(OH)₂

CCH₃CH(OH)COOH

DCH₂(COOH)₂

ECH₃COCOOH

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Question 761

waec 1991

Brass is an alloy of copper and

Airon

Bchromium

Czinc

Dtin

Emagnesium

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Question 762

waec 1991

CH₂ = CH₂ + H₂SO₄ → CH₃ - CH₂ -OSO₃H. The reaction illustrated by the equation above is an example of

Asubstitution

Boxidation

Creduction

Daddition

Edisplacement

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Question 763

waec 1991

Which of the following elements can from more than one acidic oxide?

AHydrogen

BSulphur

CCarbon

DAlumium

EIron

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Question 764

waec 1991

Which of the processes represented by the following equations has the greatest positive entropy change?

AC₆H₃_(l) → C₆H ₆ _(g)

BH₂O _(s) → H₂O_(l)

CCuO_(s) + H₂_(g) → Cu_(s) + H₂

DNa₂CO₃_(s) + nH₂O_(l) →Na ₂CO₃nH₂O_(s)

ES_(s) → S_(l)

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Question 765

waec 1991

What is the amount (in mole) of sodium trioxocarbonate (IV) in 5.3 g of the compound? (Na₂CO₃ = 106)

A0.05

B0.10

C0.20

D0.50

E2.00

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Question 766

waec 1991

When air is passed through a heated tube containing finely divided copper, the component that is absorbed in the process is

Acarbon (IV) oxide

Bnitrogen

Coxygen

Dwater vapour

Enoble gases

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Question 767

waec 1991

The separation of a mixture of calcium trioxocarbonate (lV) and sodium trioxocarbonate (IV) is most easily carried out by using the differences in their

Aphysical states

Bmelting points

CRf. values

Dsolubility

Eboiling points

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Question 768

waec 1991

In which of the following is the oxidation number of nitrogen zero?

ASO₂ and NH₃

BNaNO₃

CHNO₂

DNOI₃

EN₂

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Question 769

waec 1991

The metal extracted from cassiterite is

Acalcium

Bcopper

Ctin

Dsodium

Elead

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Question 770

waec 1990

Petrol can be obtained from diesel by

Adistillation

Bcracking

Ccatalysis

Dpolymerization

Edehydrogenation

View Explanation & Discuss

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